1. Field of the Invention
The present invention relates generally to a mobile communication system, and in particular, to a method of forwarding an SMS message in a mobile communication system.
2. Description of the Related Art
FIG. 1 is a schematic view of a typical cellular mobile communication system. Referring to FIG. 1, a base station (BS) 20 connects radio channels with a mobile station (MS), e.g., mobile terminal (or mobile subscriber, “MS”) 10. A mobile switching center (MSC) 30 receives subscriber information from a corresponding home location register (HLR) 40 and connects a call for the MS 10 to another subscriber system, for example, another MSC or the public switched telephone network (PSTN). The MSC 30 also interconnects with at least one message center (MC) 50 that provides SMS (Short Message Service) messages to the MS 10 and to other mobile subscribers.
Mobile communication system providers typically offer a forwarding service to allow a user to answer a call that is placed to the user's cellular (or mobile) phone, despite the user being unable to use his mobile terminal. The user can answer such forwarded calls by setting the call forwarding service to forward the incoming call to a predetermined destination terminal (e.g., another cellular phone, a PSTN phone, or other type of mobile terminal). Such subscription is alternatively referred to as registering or setting the forwarding service. Mobile communication systems typically provide a SMS service as an optional service to which the user may subscribe (i.e., register or set) for the called terminal. SMS services are becoming increasing popular and are utilized by a growing number of individuals due to the advantage of facing fewer constraints of call connections, as well as the other recognized conveniences of sending SMS messages.
Conventional SMS systems, however, cannot forward an SMS message, even if a forwarding function is registered for a called mobile terminal.
FIG. 2 illustrates a conventional SMS message transmitting operation.
Referring to FIG. 2, when a calling mobile terminal 10 requests transmission of an SMS message 25 to a MC 50 via a calling MSC 30, the MC 50 translates a called number received from the calling mobile terminal 10 and transmits the translated number to a corresponding MC 50. A MC 50 applies to a corresponding called Home Location Register (HLR) 40 for information about a called mobile terminal 80. The called HLR 40 searches for the subscriber information of the called mobile terminal 80. If a forwarding function is registered for the called mobile terminal 80, i.e., terminal 80 subscribes to a call forwarding service, the MC 50 will either hold the SMS message or will transmit the SMS message directly to the called mobile terminal 80. Therefore, a destination mobile terminal 90 cannot receive the SMS message and, what is worse, the SMS message may be lost permanently. The destination terminal 90 is the terminal to which the message is to be sent.
Since the conventional forwarding services do not provide forwarding of SMS messages, an SMS message cannot be forwarded to a destination mobile terminal 90 or to a destination PSTN terminal.